A doctor of the Spanish army provides medical assistance in the province of Herat, within the framework of the NATO's International Security Assistance Force, in 2010. EFE PHOTO

The Atlantic Alliance, NATO

The origin of the North Atlantic Treaty Organization (NATO) lies in the signing of the Washington Treaty of 1949 by which twelve countries from both sides of the Atlantic pledged to defend each other in the event of an attack on any of them. It currently has 29 member countries, 21 partners for cooperation in the Euro-Atlantic Partnership Council (EAPC), seven in the Mediterranean Dialogue, four countries participating in the Istanbul Cooperation Initiative (ICE) and nine partners around the world. Spain became the 16th member of NATO on 30 May 1982.

The North Atlantic Treaty Organization or Atlantic Alliance (NATO) is an international political and military organization with the aim of guaranteeing the freedom and security of its members through political and military means.